Such gear systems are usually implemented as reverse gear units and are fitted in many different construction machines, whereby the installation conditions, as a function of the type of motor vehicle, can fail differently. For example, the available fitting space, if it is extremely small, can fail. Furthermore, different axle bases between the transmission drive shaft and the transmission output shaft can occur; besides, depending on the type of motor vehicle, a certain axle placement between the entrance shaft and the output shaft of the gear system is necessary.
An excavator loader vehicle demands, for example, a compact building method due to the central installation and the clearance. A motor vehicle telescopic handler demands a slim, tall silhouette with small lateral discharges or a low building method with the possibility of the lateral expansion upon execution.
Further, in most areas of application in construction machines, at least one auxiliary drive is needed for the hydraulics of the machine, for example. The tasks, which a reverse gear unit has to fulfill, are therefore conditional by the design of the type of motor vehicle and are very different. These requirements must be fulfilled within the overall axial length and width of the transmission.
Transmissions of the kind initially specified have different requirements regarding the positions of the drive shafts and the number of the necessary forward and reverse gears.
For example, excavator loader transmissions have requirements regarding a short distance between the output shaft and the drive shaft (to the rear wheels), which is conditional to the position by the fitting space in the vehicle. Further, it should be given as much clearance as possible, which means that the engine/gear unit should sit as high as possible. With excavator loaders, in most cases, the rear wheels are clearly larger than the front wheels, whereby the vertical position of the rear axle is clearly higher than that of the front axle. Typical distances, which result, are 160-180 millimeters in the vertical direction without lateral misalignment or with a small lateral misalignment.
Excavator loaders usually exhibit an insertable front wheel drive, whereby the front wheel drive lies lower to the rear wheels due to the smaller front wheels at the transmission opposite the drift. Since the engine surface mounting is also on the front side of the transmission, there is the restriction of the building space in which the front wheel drive is arranged outside, respectively below, a converter bell.
The telescopic handler have a permanent four wheel drive. The front wheel drive is in the same position as the rear drift, whereby the transmission needs only one drive shaft. In addition to the body of the vehicle, the gears of the telescopic handlers have other requirements regarding the axle base than the excavator loader transmissions. In many cases, for example, a large lateral misalignment of the drift is necessary for drive. This demand results from the lateral installation position of the engine. Thus, a horizontal misalignment is necessary for the centric drive shaft. The bypass of the current force to the middle of the vehicle was, in most cases until now, achieved by the installation of an axle distributor gear.
A further typical installation position is possible for the centric arrangement of the gear/motor unit with telescopic handlers with a lateral construction. Here it may provide no lateral misalignment of the drift (related to the propulsion); the vertical wheel base is clearly larger opposite a telescopic handler with a transfer case, as well as opposite a gear system of an excavator loader.
From EP 0 759 129 B1 an announcement of a read-adjustable reverse gear unit is known, which exhibits a drive wheel set and a distributor wheel set in the allocation of coupling shift clutches, fixed wheels and idlers on several forward shafts, with which long and short axle bases can be realized. For long axle bases, it is proposed that the jack shafts are essential in the ordering of the drive shaft and the drive shaft, whereby, depending upon the desired gear, different combinations of jack shafts are involved in power transmission. With short axle bases, the jack shafts are positioned in a circle around the drive shaft, which is how their position to each other is already determined. With this reverse gear, different shaft arrangements are proposed for the realization of different axle bases.
Furthermore, in DE 101 31 329, a read-adjustable, more usual reverse gear unit was announced with a drive shaft, an output shaft and several jack shafts with on these idlers distributed on the shafts, fixed wheels and coupling shift clutches, which form several reduction gear units at the gearshift and direction circuit. Here the individual waves are combined into a reverse gear unit and a transmission unit, whereby the transmission unit, at any side of the drive, is proposed and the transmission unit is attached to the reverse gear unit, so that the reverse transmission unit and the transmission unit are behind each other on the drive shaft and organized on a side of the drive shaft.
With the transmission concepts being the state of the art, the axle base cannot variably arranged in an unfavorable way. Due to the clutch and shaft arrangement, as well as the engages of certain wheels, they exist with each other in a small space concerning the positioning of the wheel base (drive to drift). Often a construction modification is in order to be able to meet changed requirements to the axle base, only at the highest possible cost, which means that for the realization of different axle bases, different transmission concepts must be developed.
For example, with existing transmission concepts, it is necessary to introduce an intermediate shaft in order to come from a short vertical axle base to a large axle base. In order to obtain a large lateral misalignment, a transfer case must be cultivated.
The existing diagrams exhibit the disadvantage that the outward transmission for is only conditionally, flexibly shaped. Thus it is often impossible to satisfy a transmission concept of the requirements to the available space of the various types of motor vehicles.
Moreover, many of the usual kinds of transmissions do not exhibit the necessary flexibility, especially modularity, in order to correct the different requirements of the numbers of threads in a transmission concept. For the realization of these different numbers of threads, complex re-designs are often necessary. With some gear construction methods, it is possible, by “taking” a clutch from a 5-gear or a 6-gear transmission, to make it suitable for a 4-gear transmission. However, this does not result in a significant reduction in cost, since the concept for a 6-gear transmission is laid out.
The present invention is based on the task of creating a powershift gearbox for construction machines, especially for a tractor backhoe loader and a telescopic handlers, a task which circumvents the disadvantages of the state of the art. In particular, very small and very large axle bases are made possible. Moreover, the possible shaft arrangements of the different requirements are supposed to satisfy excavator loader transmissions and telescopic handler transmissions.